In presently available computer controlled knife cutting systems various materials are cut into desired shapes. In the normal process of automatic knife cutting, the knife is plunged down into the material to be cut. During this plunging motion, the knife may be reciprocating or non-reciprocating. The knife will then be moved in directions corresponding to the two dimensional shapes required. During the cutting motion the knife is reciprocating to provide the slicing action required to cut the material. In order to maintain smooth, efficient and accurate cutting the knives must be kept sharp. This is usually achieved by periodically applying a sharpening tool (such as a sharpening band or stone) to the knife blade.
The movement of the knives of the knife cutting system is computer controlled with the desired shapes being programmed into the cutting system. It is thus necessary for the shapes to be represented in a form that can be recognised by the system that controls the cutting knives.
Typically shapes can be represented (created) digitally in the following ways:
1. Created by computer software (Computer Aided Design CAD). This software is used in many industries and software is varied from general engineering purposes to specialised software designed for niche manufacturing applications such as furniture, apparel, footwear, gaskets, automotive seating, etc.
2. Digitising—there are many devices that are available for digitising pattern pieces. To digitise a pattern piece you need to have a pattern (original or representative to scale or not to scale). Some of the digitising devices include:                Digitising Table—this is a table that you would place a pattern onto. The operator would then trace (or click points) manually around the pattern piece whilst the pattern is resting on the table.        Digitising flatbed scanner—this can be a scanner similar to a typical office desktop scanner (often on a larger scale). The digital image is processed by computer software and the computer software will automatically determine the perimeter shape of the scanned pattern including internal markings that may represent drill holes and cut outs.        Feeding scanner—this is typically a scanner that receives a pattern piece and feeds in through a scanning device. The result is a captured image same as ‘b)’ above and the pattern image is processed by computer software and the computer software will automatically determine the perimeter shape of the scanned pattern including internal markings that may represent drill holes and cut outs.        Camera (or other image capturing device)—camera (or other image capturing device) captures the image and image same as ‘b)’ above and the pattern image is processed by computer software and the computer software will automatically determine the perimeter shape of the scanned pattern including internal markings that may represent drill holes and cut outs.        
3. In some cases, it is possible to input the shape as a digital image into programs like illustrator and Corel Draw and trace the image to generate a representation of the pattern (digitise) usable by existing cutting machines. However, because the image is presented on a computer screen which has a limited size, and given that the shapes to be digitised are often much larger than can be displayed wholly on the screen, the operator must resize and/or reposition the image several times as the digitising process takes place. This slows the process down considerably and may also introduce operator errors due to the need to manually move the image on the screen whilst undertaking the digitising process so that new area of the image can be viewed for digitising.
There are many problems with existing knife cutting systems, including, but not limited to:                Handling very small shapes—it is difficult to accurately capture the true shape;        Manual operator—errors can be introduced by the use of manual inputs to the digital capture system;        Very large shapes are difficult to fit into the size available within existing digitizing systems;        There is a lack of flexibility in the shapes able to be accommodated by existing digitizing systems.        
Further problems are associated with sharpening the knives of existing knife cutting systems. Most automatic knife sharpening systems of the prior art drive a spinning or rotating sharpening tool (such as a sharpening band or stone) which makes contact with the knife at an angle appropriate to sharpen the knife. The knife can be reciprocating or static. To sharpen the full length of the knife various methods can be used. For example, the sharpening tool may be moved along the length of the stationary blade, or alternatively the length of the blade may be moved along the stationary sharpening tool.
The abovementioned sharpening systems of the prior art include disadvantages such as:                the need to slow, delay or halt the cutting process to sharpen the knife blades, thus reducing productivity,        the sharpening is not necessarily even on each side of the knife blade,        the design complexity associated with spinning a sharpening tool, leading to a need for regular maintenance and replacement of parts due to excessive wear,        some systems fail to sharpen the knife blade along its entire cutting edge.        
Accordingly there is a need for improving the operation of knife cutting systems of the prior art.
Throughout this specification the use of the word “inventor” in singular form may be taken as reference to one (singular) inventor or more than one (plural) inventor of the present invention.
It is to be appreciated that any discussion of documents, devices, acts or knowledge in this specification is included to explain the context of the present invention. Further, the discussion throughout this specification comes about due to the realisation of the inventor and/or the identification of certain related art problems by the inventor. Moreover, any discussion of material such as documents, devices, acts or knowledge in this specification is included to explain the context of the invention in terms of the inventor's knowledge and experience and, accordingly, any such discussion should not be taken as an admission that any of the material forms part of the prior art base or the common general knowledge in the relevant art in Australia, or elsewhere, on or before the priority date of the disclosure and claims herein.